Numerous devices have been developed for assisting in the forced exercise of calf muscles. Calf muscle development techniques are illustrated in "Muscle--Builder & Power", August/September 1976, Volume 17, Number 6, Joe Weider-Editor, Woodland Hills, Calif. Some techniques include leg press machines for stretching action; a technique comprising standing with heels on a block and raising the toe as high as possible; seated toe raises with a press on the thighs for a diamond-shaped look, standing toe raises, holding dumbbells in the exerciser's hands; and "Donkey Raises" performed with two heavy training partners sitting on the exerciser's lower back while he assumes a donkey-like post with his forearms resting on a table for incredible "continuous tension" sets.
In practicing "Donkey Raises" by that prior art technique, it is impossible without the aid of training partners; it is also difficult to accurately estimate the amount of force applied.